If you plan to reuse your repository in other projects as an extension, you will need to create releases for it.

Releases mark a specific point in your repository's history and allow you to publish your extension for use by others when you think your changes are ready.

https://youtu.be/vkOWnBfBqak

In MakeCode, the each of the 3 numbers in the extension version have a special meaning. It follows a common scheme called semver.

Whenever, you see a version number like 1.3.19, it really means major version is 1, minor version is 3, and patch number is 19.

Basically, the rules of semver are, for a particular version MAJOR.MINOR.PATCH, you set the next version by incrementing the:

• MAJOR version when you make incompatible API changes.
• MINOR version when you add functionality in a backwards compatible manner.
• PATCH version when you make backwards compatible bug fixes.

Releases also upload a pre-compiled version of your application so that the GitHub pages web site can use it. You will find the file at assets/js/binary.js.

You can include an open source license in your repository to make it easier for other people to contribute.

GitHub Licensing Documentation, GitHub Releases Documentation